Recently, electronic appliances such as audio and video equipment have been improved dramatically in their performance as compared to conventional ones owing to the significant progress of digital technologies. With the performance improvement of electronic appliances, the market strongly solicits performance improvement of loudspeakers used for the appliances.
A diaphragm constitutes a great part of determining the sound quality of a loudspeaker among its component parts. For a loudspeaker the performance improvement of which is strongly solicited by the market, it is essential to improve the performance of the diaphragm and other vibrating parts.
As part of improving the performance of a diaphragm and other vibrating parts, it is extremely important to make sound and characteristics satisfying user needs by a field or application.
What implements making sound and characteristics satisfying the user needs is a paper-made component that has an advantage of fine-tuning the characteristics as a loudspeaker or sound quality, and thus developing paper-made components is receiving attention.
A description is made for conventional production equipment of paper-made components such as diaphragms, using FIGS. 14A through 14D, which are conceptual diagrams showing conventional production equipment of paper-made diaphragms for loudspeakers.
As shown in FIG. 14A, beating device 221 includes beater 201 and rotary blade 202. Material 210 of a paper-made diaphragm for a loudspeaker is inserted into beater 201 containing water, and rotary blade 202 is rotated. With this action, material 210 is beaten into fine pieces with beating device 221 spending several days.
Next, as shown in FIG. 14B, paper-making device 222 includes container 203 and mold 204. Mold 204 has wire mesh 205 arranged thereon. Material 210a beaten is skimmed onto mold 204 with paper-making device 222. This action discharges only moisture from material 210a. Further, material 210a is accumulated on mold 204 to form the shape of paper-made diaphragm 211 for a loudspeaker.
Next, as shown in FIG. 14C, pressure device 223 heat-pressurizes paper-made diaphragm 211 for a loudspeaker. Paper-made diaphragm 211 for a loudspeaker is heat-pressurized by pressure device 223, further removing moisture remaining in paper-made diaphragm 211 for a loudspeaker by vaporization.
Next, as shown in FIG. 14D, punching device 224 has stamping die 206. Paper-made diaphragm 211 for a loudspeaker with its moisture vaporized is stamped by stamping die 206 into an outermost periphery and a center hole through which a voice coil is inserted, using punching device 224. This action produces paper-made diaphragm 211a for a loudspeaker.
Here, the description is made for production equipment of press diaphragms. Meanwhile, production equipment of oven diaphragms exists, where paper-made diaphragm 211 for a loudspeaker is produced by being dried for approximately one day or two, without using pressure device 223 for press working. An oven diaphragm is called a non-press diaphragm as well.
Such conventional production equipment of paper-made components for loudspeakers is disclosed in Japanese Patent Unexamined Publication No. 2004-80465 (patent literature 1), for example. Further, a method of manufacturing an aqueous suspension of rigid straight chain synthesis polymer molecule fiber, using a pressure type homogenizer is disclosed in Japanese Patent Unexamined Publication No. S63-196790 (patent literature 2), for example.    [Patent literature 1] Japanese Patent Unexamined Publication No. 2004-80465    [Patent literature 2] Japanese Patent Unexamined Publication No. S63-196790